JP2000297980A - Refrigerator and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refrigerator having a heat insulating member arranged between an outer box and an inner box and a heat insulating wall filling the space between the heat insulating member and the inner and outer boxed in which reliability is enhanced by providing a connecting member for bonding the inner side face of the outer box and the heat insulating member between them thereby eliminating stripping. SOLUTION: In a heat insulating housing for refrigerator, a vacuum heat insulating panel 4 is pasted through a bonding agent 5 to the inner face side of an outer box 2 made of an iron plate at the gap between the outer box and a plastic inner box 3. The air gap between the heat insulating panel 4 and the inner and outer boxes 2, 3 is filled with a heat insulating wall of hard urethane foam 6. When the heat insulating panel 4 is formed, the pasting face is coated with a solvent free acryl resin emulsion adhesive 5 and dried and then the heat insulating panel 4 is secured temporarily by means of a temporary stopping tape 7. After the inner box 3 is fixed and heated preliminarily, the air gap is filled with hard urethane foam 6 and the heat insulating panel 4 is bonded rigidly to the outer box 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus such as a refrigerator, a freezer, and a freezing warehouse having a heat insulator filled and formed.

[0002]

2. Description of the Related Art Conventionally, urethane foam filled between an inner box and an outer box has been employed as a heat insulating material for refrigerators. Since the thermal conductivity of the urethane foam itself is controlled by the foaming agent used, there is a limit in further improving the heat insulating performance. The thermal conductivity of currently used rigid urethane foam is about 16 to 19 (mw / mk). Therefore, in order to further improve the heat insulation performance of refrigerators, vacuum insulation panels are known in which the heat conductivity is reduced by depressurizing the inside, and the heat conductivity is reduced to about 7 to 8 (mW / mK). Can be

Here, in order to prevent deformation at the time of decompression, a vacuum heat insulation panel is used in which a silica powder or open-cell urethane foam which is cut into a plate shape is used as a core material. A getter agent that absorbs generated moisture and gas components to prevent deterioration of the degree of vacuum may be used. The core material and the getter agent are pre-enclosed in an aluminum laminated film, and the whole is subjected to vacuum depressurization, and then the laminated film is thermally welded to form a vacuum heat insulating panel. For this reason, as a vacuum insulation panel installation place, it is a bent product of an iron plate which has no problem in strength and is excellent in sticking workability as compared with the inner box side which is a vacuum molded product of ABS resin having a complicated shape and poor strength. It is common to fix the inner surface of the outer box with an adhesive or the like, then assemble the outer box and the inner box, and fill a gap between them with urethane foam to produce a refrigerator.

[0004] A method of floating and fixing between the outer box and the inner box is also conceivable, but there is a problem in terms of cost since it is not suitable for automation due to the addition of fixing parts and poor sticking workability.
Such a method of attaching a vacuum heat insulating panel is disclosed in, for example, JP-A-61-091481.

[0005]

When a vacuum heat insulating panel is used as a refrigerator heat insulating material, it is necessary to firmly fix the vacuum heat insulating panel to the inner surface of the outer box with an adhesive or the like.
When a solvent-type adhesive is used as the adhesive, the solvent permeates the inside of the vacuum panel from the plastic layer of the vacuum panel outer packaging material and lowers the degree of vacuum, lowering the heat insulation performance, and reducing the work time. Since it is necessary to take safety measures against organic solvents, it is common and often used to use non-solvent hot-melt adhesives and pressure-sensitive adhesives.

However, according to the above-mentioned conventional technology, the adhesive strength of the hot-melt adhesive or pressure-sensitive adhesive at a temperature range of -15.degree. C. to 60.degree. Because the strength is not enough, peeling occurs at the adhesive part between the heat insulation panel and the outer box, unevenness occurs on the refrigerator outer plate, and the appearance of the refrigerator is damaged, or the strength of the box decreases, No consideration has been given to the point that the problem of reduced reliability occurs. Furthermore, if an adhesive-based adhesive is used during assembly work, the release paper must be discarded because the release paper is attached, which raises the problem of waste disposal. In addition, there is a problem that the release paper is uneconomical due to high cost. Further, when a hot-melt adhesive is used, there is a problem that the adhesive strength in a high-temperature region is reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a highly reliable refrigerator or a method of manufacturing a highly reliable refrigerator.

[0008]

An object of the present invention is to provide an outer box, an inner box, a heat insulating member disposed between the outer box and the inner box, and a heat insulating member, the inner box, and the outer box. This is achieved by providing a connecting member disposed between the inner surface of the outer box and the heat insulating member and fixing the same to each other. Further, this is achieved by the connection member including a solventless acrylic resin emulsion.

Further, in the method for manufacturing a refrigerator, a heat insulating member is arranged between the outer box and the inner box, and then a heat insulating material is filled between the outer box, the inner box and the heat insulating member. This is achieved by disposing a connecting member between the member and the outer box that becomes harder as the temperature rises, connecting the heat insulating member and the outer box, and then filling the heat insulating material. Further, this is achieved by heating the connecting member when filling the heat insulating material.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an embodiment applied to a heat insulating box for a refrigerator. FIG. 2 is a plan view of the cross section of FIG. In FIG. 1, a vacuum heat insulating panel 4 is attached by an adhesive 5 to an inner surface side of an outer box iron plate in a gap portion between an outer box 2 and a plastic inner box 3, and a gap portion is filled with a hard urethane foam 6. is there.

Here, the vacuum insulation panel 4 is formed, for example, in the following procedure. First, a solvent-free acrylic resin emulsion adhesive 5 is uniformly applied to the application surface with a brush or a spray gun or the like.
Dry for minutes. At this time, the amount of the adhesive applied is such that the applied amount of the adhesive 5 after drying is 1 g / m2 to 30 g / m2.
It is adjusted to be in the range of m2. Next, a part of the vacuum heat insulating panel 4 is temporarily fixed to the inner surface side of the outer box 2 as shown in FIG. This is because, in this state, the adhesive force for holding the adhered material on the surface of the adhesive 5 is small at this time, so that it cannot be attached to the outer plate as it is. Thereafter, a front assembled box body before the inner box 3 is assembled and the foamed heat insulating material is foamed is manufactured. Next, this front assembly box body is attached to a jig where the box body is set when foaming foam insulation material called hiring,
After the preheating, the rigid urethane foam 6 as a foam heat insulating material is filled in the gap between the inner box and the outer box.

During this foam filling, the vacuum insulation panel 4 and the outer box are firmly joined and fixed. That is, a chemical reaction occurs between the isocyanate, which is a component of the rigid urethane foam, which is a foamed heat insulating material, and the polyol. The temperature of the joint surface between the inner surface of the outer box 2 and the vacuum panel 4 rises due to the reaction heat generated at that time, and is heated to, for example, 60 ° C. or more. Then, the acrylic resin emulsion adhesive 5 applied to the joint surface is melted, the tackiness is increased and the adhesive force is increased, and the vacuum panel 4 is adhered to the inner surface of the outer box 2 and is pressed by urethane foam foaming pressure. hand,
The vacuum panel 4 is firmly fixed to the inner surface of the outer box 2. Therefore, the vacuum heat insulating panel 4 is firmly fixed to the inner surface of the outer box 2 by the adhesive 5 in a form completely covered with the hard urethane foam 6, thereby forming the heat insulating box of the refrigerator.

If the acrylic resin emulsion adhesive 5 has the property of melting at room temperature and exhibiting tackiness, it will exhibit tackiness depending on the working temperature conditions before the vacuum panel is attached. Therefore, the workability is deteriorated by sticking to other members attached to the device, and it is desirable that the temperature at which the material melts and becomes sticky is 60 ° C. or more. Conversely, if the temperature at which the adhesive is melted and becomes sticky is too high, the bonding surface between the outer box 2 and the vacuum insulation panel 4 does not reach the temperature due to the heating by the reaction heat during foaming of the urethane foam, and the adhesive 5 Is not melted, and the vacuum insulation panel 4 may not be fixed sufficiently. Therefore, the melting temperature is desirably set to 90 ° C. or less.

Table 1 shows the results obtained by measuring the adhesive strength of the acrylic resin emulsion adhesive used in this embodiment at −15 ° C., 23 ° C. and 60 ° C. using a tensile tester. The adhesive strength of a general-purpose ethylene-vinyl acetate copolymer-based hot melt adhesive as Comparative Example 1 and a double-sided tape adhesive as Comparative Example 2 were simultaneously measured in the same manner as in Example 1, and the results are shown in Table 1.

[0015]

[Table 1]

As apparent from Table 1, the acrylic resin emulsion adhesive of Example 1 has an adhesive strength of -15.
The critical stress at which the adhesion between the vacuum panel and the inner surface of the outer box does not peel is 0.0
It is 98 MPa or more, and has excellent adhesive strength. On the other hand, the critical stress of the general-purpose ethylene-vinyl acetate copolymer-based hot melt adhesive of Comparative Example 1 was 0.06 MPa.
The critical stress of the double-sided adhesive tape is 0.05MPa
It is. That is, it can be seen that the adhesive strength between the vacuum insulation panel and the outer box in the refrigerator according to the present embodiment is superior to these.

Further, a refrigerator-completed product in which refrigerator parts are attached to the heat-insulating box manufactured in the present embodiment is -15 ° C, 23 ° C,
A 10-day standing test at each temperature of 60 ° C.
Table 2 shows the results of a test in which the presence or absence of irregularities such as swelling and dents on the outer panel surface of the vacuum panel attachment portion of the refrigerator after 0 days was used to determine whether or not the adhesive portion between the vacuum panel and the outer panel had separated. . As Comparative Example 1, a refrigerator manufactured by attaching a vacuum panel to an outer plate using a general-purpose ethylene-vinyl acetate copolymer-based hot melt adhesive was used.
A refrigerator prepared by attaching a vacuum panel to an outer plate using a double-sided adhesive tape was also tested for peeling of the bonded portion between the vacuum panel and the outer plate at the same time as in Example 1 and shown in Table 2. Was.

[0018]

[Table 2]

As is clear from Table 2, the acrylic resin emulsion adhesive of Example 1 has a temperature of -15 ° C., 23 ° C., 60 ° C.
After the 10-day standing test at each temperature of ° C., no irregularities occurred on the outer panel surface of the vacuum panel attachment portion of the refrigerator.
On the other hand, the general-purpose ethylene-vinyl acetate copolymer-based hot melt adhesive of Comparative Example 1 and the double-sided tape adhesive of Comparative Example 2 were 2
There was no peeling at 3 ° C, but peeling occurred at -15 ° C and 60 ° C. From these results, it can be seen that in the refrigerator according to the present embodiment, the bonding portion between the vacuum panel and the outer plate has an excellent bonding strength with little peeling as compared with the refrigerator according to the conventional technology.

The adhesive is applied to the vacuum panel and dried, and the adhesive is heated and melted to a temperature of 50 ° C. or more by a heater such as a drier before the outer plate is attached to the outer panel in a state where the adhesive is generated. Then, even if a refrigerator box is manufactured in the same manner as in the first embodiment, the effect of firmly bonding the outer box and the vacuum heat insulating panel can be exerted as in the above embodiment. At this time, even if the adhesion to the vacuum panel surface is incomplete at the time of attaching the outer box, since it is heated by the subsequent urethane reaction heat and is pressed by the foaming pressure, the heat insulating box after urethane foaming is used. Are more strongly bonded.

If there are irregularities on both or one of the outer box attaching surface and the vacuum panel attaching surface, and the adhesive cannot be applied uniformly to the adhesive surface, the paper may be incomplete. Alternatively, the same effect can be obtained even if a non-woven fabric or the like impregnated with an acrylic resin emulsion adhesive is dried, sandwiched between bonding surfaces, and bonded in the same manner as in the above-described embodiment.

[0022]

According to the present invention, a highly reliable refrigerator or a method for manufacturing a highly reliable refrigerator can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat insulating box for a refrigerator according to the present invention.

FIG. 2 is a plan view of the transverse section of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulated box body for refrigerators 2 ... Outer box 3 ... Inner box 4 ... Vacuum insulation panel 5 ... Adhesive 6 ... Hard urethane foam 7 ... Temporary fixing tape

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Katsumi Fukuda 800 Tomita, Ohira-machi, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture F-term (Ref.) 3L102 JA00 LB01 LB26 LB31 MA01 MA07 MB12 MB27

Claims (4)

[Claims] 1. An outer box, an inner box, a heat insulating member disposed between the outer box and the inner box, and a space filled between the heat insulating member and the inner box and the outer box. A refrigerator comprising: a heat insulating wall; and a connecting member disposed between an inner surface of the outer box and the heat insulating member to fix the heat insulating member. 2. The refrigerator according to claim 1, wherein said connection member includes a solvent-free acrylic resin emulsion. 3. A method for manufacturing a refrigerator, comprising: placing an insulating member between an outer box and an inner box; and then filling a heat insulating material between the outer box, the inner box, and the insulating member. A method for manufacturing a refrigerator, comprising: disposing a connection member that becomes harder as the temperature rises between a member and the outer box, connecting the heat insulating member and the outer box, and then filling the heat insulating material. 4. The method according to claim 3, wherein the connecting member is heated when the heat insulating material is filled.